This Invention relates to manufacture of semiconductor chips using X-rays, and particularly to the fabrication of patterned membrane X-ray masks and their use.
Forming patterned images on semiconductor chips with X-rays through X-ray masks offers a number of advantages. X-rays can form more precise images than visible or ultra-violet light because they do not suffer as much diffraction as the latter. X-ray images are thus more precise than other images and avoid the imperfections that can ruin a chip. As is known, a single imperfection can ruin a semiconductor chip, and the use of X-rays increases the statistical yields of perfect chips. X-rays also may make increased packing densities possible.
Patterned X-ray membrane masks are used to form images with X-rays. In the past, such patterned X-ray membrane masks have been manufactured by depositing X-ray absorbing materials such as tantalum, gold, tungsten, etc. on the surfaces of silicon membranes.
While such patterned membrane X-ray masks have proven successful for many applications, they exhibit a number of disadvantages, both in fabrication and use.